title: Correlation and prediction of partition coefficient using nonrandom two-liquid segment activity coefficient model for solvent system selection in counter-current chromatography separation.
abstract: Selection of a suitable solvent system is the first and foremost step for a successful counter-current chromatography (CCC) separation. In this paper, a thermodynamic model, nonrandom two-liquid segment activity coefficient model (NRTL-SAC) which uses four types of conceptual segments to describe the effective surface interactions for each solvent and solute molecule, was employed to correlate and predict the partition coefficients (K) of a given compound in a specific solvent system. Then a suitable solvent system was selected according to the predicted partition coefficients. Three solvent system families, heptane/methanol/water, heptane/ethyl acetate/methanol/water (Arizona) and hexane/ethyl acetate/methanol/water, and several solutes were selected to investigate the effectiveness of the NRTL-SAC model for predicting the partition coefficients. Comparison between experimental results and predicted results showed that the NRTL-SAC model is of potential for estimating the K value of a given compound. Also a practical separation case on magnolol and honokiol suggests the NRTL-SAC model is effective, reliable and practical for the purpose of predicting partition coefficients and selecting a suitable solvent system for CCC separation.
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China.
authors.forename: Da-Bing
authors.initials: DB
authors.lastname: Ren
authors.forename: Zhao-Hui
authors.initials: ZH
authors.lastname: Yang
authors.forename: Yi-Zeng
authors.initials: YZ
authors.lastname: Liang
authors.forename: Qiong
authors.initials: Q
authors.lastname: Ding
authors.forename: Chen
authors.initials: C
authors.lastname: Chen
authors.forename: Mei-Lan
authors.initials: ML
authors.lastname: Ouyang
mesh_terms: D003377:Countercurrent Distribution / Q000379:methods*; D031566:Magnolia / Q000737:chemistry; D008956:Models, Chemical; D009930:Organic Chemicals / Q000737:chemistry* / Q000302:isolation & purification; D004364:Pharmaceutical Preparations / Q000302:isolation & purification; D010936:Plant Extracts / Q000302:isolation & purification; D012997:Solvents / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D009930:Organic Chemicals; D004364:Pharmaceutical Preparations; D010936:Plant Extracts; D012997:Solvents
keywords: Counter-current chromatography; NRTL-SAC model; Partition coefficient; Prediction; Solvent system selection